There have been demands for a nonaqueous electrolyte secondary battery having high capacities with which the batteries can be used for a prolonged period of time and improved output characteristics with which the batteries are capable of being charged and discharged with a large current in a relatively short period of time.
For example, PTL 1 suggests that depositing an element belonging to Group 3 of the periodic table on the surfaces of base particles of a positive electrode active material may limit the reaction between the positive electrode active material and an electrolyte solution even when the charging voltage is high and this may limit the degradation of the charge-conservation characteristics.
For example, PTL 2 suggests that adding NaF to the inside of a battery case (to a positive electrode, a negative electrode, or an electrolyte solution) may reduce the cycle degradation caused by the reaction between, for example, HF and a positive electrode active material and, as a result, enhance the cycle characteristics (capacity maintenance ratio).